Oncocytic meningiomas: cases with benign histopathological features and favourable clinical course

OBJECT Oncocytic meningioma has recently been recognized as a distinct morphological variant of intracranial meningothelial neoplasms, and only a few cases have been reported in the literature. The first description of this lesion, which was based on data in six cases, revealed a potentially aggressive nature with a tendency to infiltrate the brain and to recur. However, the true behavior of, and the long-term follow-up data for, such lesions must still be outlined. METHODS The authors report on five cases of intracranial oncocytic meningiomas. On neuroimaging, the lesions showed the characteristic features of common meningiomas. All patients underwent gross-total removal of the mass together with the adjacent dura mater. No additional treatments were administered. Histologically, the tumors were composed of sheets, nests, and cords of large polygonal neoplastic cells with finely granular cytoplasm. Necrosis was absent in all cases. Mitosis was also absent or exceedingly rare, and no brain cortex infiltration was observed. The follow up ranged from 6 to 54 months (mean 32.4 months). At the last follow-up evaluation, all patients were asymptomatic and magnetic resonance imaging examinations demonstrated no evidence of tumor recurrence. CONCLUSIONS Data in the presented cases did not confirm a previously described propensity to aggressiveness in this meningioma subtype. In fact, the histological features as well as the long-term favorable clinical course may suggest benign behavior of such neoplasms, as in the common forms of meningiomas.